This invention relates to an ultrasonic medical treatment apparatus for use in medical treatment of patients, by radiating ultrasonic waves onto the location of a calculus or tumor within the patient's body, and, more particularly, to an ultrasonic medical treatment apparatus which generates three-dimensional image data to enlarge a field of the region of interest of the patient to be treated.
Most importantly, an ultrasonic treatment apparatus must be able to focus ultrasonic waves precisely on the region of interest (ROI) and to radiate it with ultrasonic waves. A prior art of this invention is U.S. Pat. No. 4,617,931. In this patent, a probe for the B-mode is located at the center of the group of ultrasonic therapeutic transducers to obtain the image of only the tomogram extending in the direction of the depth of the patient's body, i.e., the B-mode tomogram. While seeing the tomogram, an operator monitors the ROI and positions the medical treatment ultrasonic transducer. If breathing or movement of the body occurs when using the prior art apparatus, correction of the moved ROI location must be performed and is a troublesome operation. Further, when the body movement is great, the ROI may go out of the field of view. In this case, it is very difficult to obtain the ROI and to set it within the field. The prior art contains examples of apparatus which are able to monitor a ROI in a three-dimensional manner. Such an apparatus uses B-mode probes arranged such that their scanning surfaces are orthogonal to each other. An improved apparatus of this type is disclosed in Japanese Patent Disclosure No. 59-101143. This apparatus can obtain at least two ultrasonic B-mode tomographic images arranged orthogonally. By using a main beam, whose position against either of those images is known precisely, a ROI whose position varies with time can be traced continuously, in a three-dimensional manner and in real time, even when the region of interest varies with the passage of time. In the prior art, for example, when the body moves and the position to be treated moves accordingly, the movement of the position can be detected at any moment by the two B-mode probes, but the field is narrow, and when the ROI is once out of the field, it is very difficult to find it again.